Steam turbine blades are affected by heavy water droplet erosion (WDE). Similarly, gas turbine blades are affected by corrosion. This disclosure relates to forming a blade having an insert welded to a leading edge and/or a trailing edge of an airfoil. This insert can be used to repair heavy erosion or corrosion with a reduced cost with respect to other methodologies with a lower risk of cracking.
Current methods of repairing turbine blades have a number of disadvantages. For example, some current methods for repairing WDE fail to repair the leading edge section nearest the shroud. The leading edge nearest the shroud is typically the section of the airfoil that experiences the highest WDE. It is very important to maintain original material shapes and characteristics in this section of the blade. During a repair, a weld may be used to attach a replacement leading edge to the airfoil. The weld creates high temperatures in the blade material and the high temperatures can cause deformations and other undesirable changes in the shroud material, for example, causing the material to become brittle. Since welding near the shroud causes undesirable heat damage, conventional blade repair does not address the leading edge nearest the shroud.
In examples that do address the leading edge of the airfoil nearest the shroud, the entire shroud is replaced. This type of repair method includes added costs of materials and machining.